GB2284245A

GB2284245A - A toothed gearwheel

Info

Publication number: GB2284245A
Application number: GB9423285A
Authority: GB
Inventors: Albrecht Schnizler
Original assignee: Metabowerke GmbH and Co
Current assignee: Metabowerke GmbH and Co
Priority date: 1993-11-29
Filing date: 1994-11-18
Publication date: 1995-05-31
Anticipated expiration: 2014-11-18
Also published as: ITMI942393A0; GB2284245B; US5493930A; DE4340527C1; IT1271096B; FR2713298A1; GB9423285D0; FR2713298B1; ITMI942393A1

Abstract

A toothed gearwheel 3 has a coaxial trough 5 open at an end face forming at least one storage chamber 6, 7 for grease. This storage chamber is closed by a lid 8, 9 adjoined by a leakage path for the grease which extends up to adjacent the teeth 4 of the gearwheel. For a better quantity and timed-controlled metering of the grease the trough 5 of the gearwheel has axially in succession an inner storage chamber 6 filled with grease and an outer storage chamber 7. Both storage chambers are closed by lids 8, 9 which with their circumferential faces sealingly adjoin the radially outwardly lying inner wall of the trough 5. A narrow groove 16 for the passage of the lubricant extends over the circumferential surface of each lid 8, 9. <IMAGE>

Description

2284245 Toothed gear wheel The invention relates to a toothed gear wheel

with centrifugal force lubrication.

The invention is particularly concerned with toothed gearing for the reduction of high speed drive motors, more particularly of electric tools, where at least one gearwheel meshes with a counter wheel or pinion and has on or near its outer circumference a spur gear. A coaxial trough is open at one end face for at least one storage chamber for grease which is closed by a lid adjoined by a leakage path extending up to the spur gear of the gearwheel f or the grease which is supplied by means of centrifugal force.

is A toothed gear of this kind is known f rom DE 41 12 843. There the coaxial trough of the gearwheel only encloses a single storage chamber for the grease, and the lid of the trough is formed by a disc-like cover which adjoins the end side of the gearwheel towards which the trough opens. In the contact area between this cover and the corresponding bearing face of the gearwheel there are one or more radially outwardly directed leakage paths 3 which can be formed by a hair gap between the contact bearing face of the gearwheel and the cover. During rotation of the gearwheel the grease located in the single storage chamber migrates as a result of the centrifugal action towards the radial outlet gaps and passes from there without further obstruction to the lubricating points on the spur gear.

In practice it happens that with the known toothed gearing the grease in the storage chamber is used up too quickly, and that the lubricating action occurs even when the gearing is new and has sufficient lubricant applied directly to the spur gears of the gearwheels during the manufacturing SP1474. P3 14 November 1994 process.

The object of the present invention is to provide a toothed gear with centrifugal force lubrication of the kind already mentioned wherein the amount of grease emerging f rom the storage chamber can be more finely metered and only passes to the lubricating points on the spur gear of the gearwheel af ter a certain running time of the relevant machine has lapsed.

According to the invention, there is provided a toothed gearwheel having on or near its outer circumference a spur gear and which has a coaxial trough open at an end face to form a storage chamber for grease, the trough being closed is by a lid adjoined by a leakage path extending up to the spur gear of the gearwheel, wherein in the trough in succession in the axial direction are an inner storage chamber filled with grease, and an outer storage chamber wherein the inner storage chamber is separated f rom the outer storage chamber by an inner lid and the outer storage chamber is separated f rom the outside by an outer lid, wherein the two lids tightly adjoin through a circumferential surface the radially outer internal wall of the trough and a narrow groove extends from inwards outwards over these circumferential surfaces of the two lids.

In the new or starting state of the toothed gear the lubricant is only located in the inner storage chamber, is at first moved into the outer storage chamber in a measured amount through centrifugal force and from there only passes out through the leakage paths to the lubricating points after further metering. The fine metering is produced through the calibration of the narrow grooves on the circumferential faces of the lids closing the two storage chambers, and the time delay up to the grease.reaching the SP1474. P3 14 November 1994 lubricating points is produced by the temporary store of the grease in the outer storage chamber.

Possibilities f or variations, more particularly regarding the time length which elapses until the grease penetrates the lubricating points, are produced from the relative alignment of the outlet opening of the groove of the inner lid and the inlet opening of the groove of the outer lid in the circumferential direction of the trough, thus these two openings can be aligned axially parallel with each other or can be off- set from each other by an angle wherein the longest lasting path of the grease from the inner storage chamber to the lubricating points is produced when the stagger between the outlet opening of the groove of the is inner lid and the inlet opening of the groove of the outer lid amounts to 1800.

Also the path of the grooves over the circumferential faces of the two lids f rom each inside to each outside can have an ef f ect on the metered amount and outlet speed of the grease.

Thus the grooves can be inclined to the circumferential face of the two lids opposite to or in the direction of rotation of the gearwheel but in a preferred embodiment the grooves run axially parallel over the circumferential faces of the two lids.

So that sufficiently wide circumferential faces can be formed by simple means for close contact against the inner wall of the trough of the gearwheel and for adequate length of the grooves for the grease passage, the inner lid and outer lid are formed pot-shaped wherein the circumferential faces are located with the grooves on the outsides of the pot walls. Thus the pot-shaped lids can be drawn sheet steel parts and one identical design can be used for both 35 lids when the trough of the gearwheel is f ormed by a SP1474. P3 14 November 1994 - 4 cylindrical ring groove.

The invention will now be explained with reference to an embodiment shown in the drawing in which: 5 Figure 1 is a sectional view of a spur gear arrangement, as used for example in drilling machines; Figure 2 is a sectional view though the spur wheel of the gearing according to Figure 1; Figure 3 is a view of one of the lids f or closing the storage chambers for the grease in the spur wheel of the gearing according to Figure 1; Figure 3a shows an enlarged detail of the circumferential side of the lid according to Figure 3; is Figure 4 is a sectional view through the lid according to Figure 3; and Figure 4a shows on an enlarged scale the edge area of the lid in the sectional view according to Figure 4.

Figure 1 shows in detail a pinion 1 which is seated on an engine output shaf t not shown in further detail. The pinion 1 meshes through its outer teeth 2 with the teeth 4 on the circumference of a spur wheel 3 which is seated on an output shaft not shown in further detail.

The spur wheel 3 shown per se in Figure 2 has in the form of a ring groove cut f rom. one of the two end sides with cylindrical inner and outer flanks a trough 5 which as can be seen in more detail from Figure 1 houses an inner storage chamber 6 and outer storage chamber 7. The inner storage chamber 6 is divided from the outer storage chamber 7 by an inner lid 8 and the outer storage chamber 7 is closed from the outside by an outer lid 9 which is identical with the inner lid 8. In the starting or new state of the gearing the inner storage chamber 6 is filled with grease which as SP1474. P3 14 November 1994 a result of the effects of centrifugal force migrates from there, in the manner to be explained in detail below, into the outer storage chamber 7 from where it then passes through a leakage path 10 at one end side of the spur wheel 3 up to the lubricating points in the area of the intermeshing teeth 2 and 4.

Figures 3 and 4 show details of the lids 8 and 9 which are used to close the storage chambers 6 and 7. As drawn pot- shaped sheet steel parts the lids 8,9 have an end disc 13 with central opening 14 and a cylindrical pot wall 15 angled at right angles therefrom. The pot wall 15 thus also has a cylindrical circumferential face 12 which when the lids 8 and 9 are inserted into the trough 5 sealingly adjoins the cylindrical wall 11 of the trough 5 which, seen radially is located on the outside.

As can be seen in particular from the enlarged illustrations of Figures 3a and 4a a narrow groove 16 extends axially parallel over the circumferential face 12 on the outside of the pot wall 15. This groove 16 can also have the shape of a notch or channel which serves f or the passage of the grease f rom the inner storage chamber 6 to the outer storage chamber 7 and from there to the outside. Metering of the grease which is f orced through as a result of centrifugal force can only be carried out over the passage cross-section of these grooves 16 on the circumferential faces 12 of the two lids 8 and 9. Since each of the lids 8 and 9 preferably has only one single groove 16 on its circumferential face 12 it is still additionally possible by rotating the lid 8 which closes the inner storage chamber 6 in relation to the lid 9 which closes the outer storage chamber 7 from the outside, to shorten or lengthen the leakage path for the grease through the outer storage chamber 7, depending on whether the grooves 16 on the SP1474. P3 14 November 1994 circumf erential f aces 12 of the two lids 8 and 9 align axially with each other or are of f -set more or less f rom each other seen in the circumferential direction of the trough 5. The longest leakage path through the outer storage chamber 7 can be achieved if the stagger between the grooves 16 of the inner lid 8 and outer lid 9 amounts to 1800.

SP1474. P3 14 NOvember 1994 7

Claims

PATENT CLAIMS:

1. A toothed gearwheel having on or near its outer circumference a spur gear and which has a coaxial trough open at an end face to form a storage chamber for grease, the trough being closed by a lid adjoined by a leakage path extending up to the spur gear of the gearwheel, wherein in the trough in succession in the axial direction are an inner storage chamber f illed with grease, and an outer storage chamber wherein the inner storage chamber is separated f rom the outer storage chamber by an inner lid and the outer storage chamber is separated from the outside by an outer lid, wherein the two lids tightly adjoin through a circumferential surface the radially outer internal wall of is the trough and a narrow groove extends from inwards outwards over these circumferential surfaces of the two lids.

2. Toothed gearwheel according to Claim 1, wherein the outlet opening of the groove of the inner lid is aligned axially parallel with the inlet opening of the groove of the outer lid.

3. Toothed gearwheel according to Claim 1, wherein the outlet opening of the groove of the inner lid is off-set by an angle in the circumferential direction from the inlet opening of the groove of the outer lid.

4. Toothed gearwheel according to Claim 3, wherein the stagger between the outlet opening of the groove of the inner lid and the inlet opening of the groove of the outer lid is 1800.

5. Toothed gearwheel according to any one of Claims 1 to 4, wherein the grooves run axially parallel over the circumferential faces of the two lids.

SP1474. P3 14 November 1994

6. Toothed gearwheel according to any one of Claims 1 to 5, wherein the two lids are pot-shaped and the circumferential faces are located with the grooves on the outsides of the pot walls.

7. Toothed gearwheel according to Claim 6, wherein the potshaped lids are drawn sheet metal parts.

8. Toothed gearwheel according to any one of Claims 1 to 7, wherein the trough of the gearwheel is a cylindrical ring groove and the two lids are identical.

9. A toothed gearwheel substantially as herein described with reference to the accompanying drawings.

S P1474. P3 14 November 1994